The Influence of Rheological Parameters in Wax Deposition in Channel Flow

2010 ◽  
Author(s):  
L. R. Minchola ◽  
L. F. A. Azevedo ◽  
A. O. Nieckele
Keyword(s):  
Rheological Properties ◽  
Molecular Diffusion ◽  
Rectangular Channel ◽  
Rheological Parameters ◽  
Efficient Design ◽  
Wax Deposition ◽  
Deposition Mechanism ◽  
Cold Environments ◽  
Operational Problem ◽  
Newtonian Behavior

Wax deposition is a critical operational problem in crude oil transportation through pipelines in cold environments. Accurate prediction of the wax deposition is crucial for the efficient design of subsea lines. Wax deposition is a complex process for which the basic mechanisms are still not fully understood. Although Fick’s molecular diffusion model is considered by several authors as the leading deposition mechanism, it is shown that it does not represent well the wax deposition thickness, measured during the transient regime, in a simple experiment, in a rectangular channel, with a laboratory oil-wax mixture. Another important wax deposition mechanism identified is associated with the rheological properties of the fluid, since oil-paraffin mixtures shows a non-Newtonian behavior at temperatures below the fluid Wax Appearance Temperature. The mixture can be modeled as a Bingham fluid, with a dependence of the yield stress on wax concentration, temperature and rate of cooling. The present paper presents a numerical model for predicting wax deposition in channel flows considering the influence of rheological properties combined with a diffusion-based deposition mechanism. To determine the amount of deposit, the conservation equations of mass, momentum, energy and wax concentration in the mixture were numerically solved with the finite volume method. A nonorthogonal moving coordinate system that adapts to the wax interface deposit geometry was employed. The results demonstrated that additional deposition is obtained as a result of the non Newtonian behavior of the fluid. This trend is in agreement with experimental observation conducted in previous studies.

scholarly journals Influence of biopolymers on the rheological properties of seafloor sediments and the runout behavior of submarine debris flows

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jun Kameda ◽  
Hamada Yohei
Keyword(s):  
Rheological Properties ◽  
Debris Flows ◽  
Extracellular Polymeric Substances ◽  
Flow Behavior ◽  
Mass Movement ◽  
Rheological Parameters ◽  
Natural Environments ◽  
Natural Systems ◽  
Chemical Conditions ◽  
Seafloor Sediments

AbstractSubmarine debris flows are mass movement processes on the seafloor, and are geohazards for seafloor infrastructure such as pipelines, communication cables, and submarine structures. Understanding the generation and run-out behavior of submarine debris flows is thus critical for assessing the risk of such geohazards. The rheological properties of seafloor sediments are governed by factors including sediment composition, grain size, water content, and physico-chemical conditions. In addition, extracellular polymeric substances (EPS) generated by microorganisms can affect rheological properties in natural systems. Here we show that a small quantity of EPS (~ 0.1 wt%) can potentially increase slope stability and decrease the mobility of submarine debris flows by increasing the internal cohesion of seafloor sediment. Our experiments demonstrated that the flow behavior of sediment suspensions mixed with an analogue material of EPS (xanthan gum) can be described by a Herschel–Bulkley model, with the rheological parameters being modified progressively, but not monotonously, with increasing EPS content. Numerical modeling of debris flows demonstrated that the run-out distance markedly decreases if even 0.1 wt% of EPS is added. The addition of EPS can also enhance the resistivity of sediment to fluidization triggered by cyclic loading, by means of formation of an EPS network that binds sediment particles. These findings suggest that the presence of EPS in natural environments reduces the likelihood of submarine geohazards.

Study of the physical, chemical and rheological properties of oil mixtures transported through the Uzen - Atyrau - Samara pipeline

2021 ◽  
pp. 420-427
Author(s):  
Берик Картанбаевич Саяхов ◽  
Александр Геннадьевич Дидух ◽  
Гульнара Амангельдиевна Габсаттарова ◽  
Марат Давлетович Насибулин ◽  
Жасулан Канатович Наурузбеков
Keyword(s):  
Rheological Properties ◽  
Pour Point ◽  
Heating Temperature ◽  
High Viscosity ◽  
Rheological Parameters ◽  
Polarization Microscopy ◽  
Oil Pipeline ◽  
Physical Chemical ◽  
Wide Range ◽  
Oil Mixtures

На начальных участках магистрального нефтепровода Узень - Атырау - Самара формируются партии низкозастывающих бузачинских и высокозастывающих мангышлакских нефтей. По маршруту транспортировки осуществляются дополнительные подкачки нефтей с различными физико-химическими и реологическими характеристиками, что может оказывать существенное влияние на свойства перекачиваемых нефтесмесей. Цель настоящей работы - исследование физико-химических и реологических свойств бузачинской и мангышлакской нефтесмесей на маршруте поставки Узень - Атырау, а также диапазона и причин изменений характеристик бузачинской нефти (основной в компонентном составе нефтесмесей, перекачиваемых по нефтепроводу Узень - Атырау - Самара). По результатам исследований установлено, что свойства мангышлакской нефтесмеси изменяются в незначительных пределах. Для бузачинской нефтесмеси свойственна нестабильность реологических параметров, которые могут изменяться в широком диапазоне в результате путевой подкачки на различных участках нефтепровода. Колебания реологических параметров наиболее показательных проб партий бузачинской нефтесмеси рекомендуется учитывать для решения задач повышения текучести высоковязких нефтей и оптимизации технологических режимов работы трубопроводов, по которым осуществляется перекачка таких нефтей. Методами газохроматографического анализа молекулярно-массового распределения тугоплавких парафинов и поляризационной микроскопии определена температура нагрева бузачинской и мангышлакской нефтесмесей, оптимальная для ввода депрессорной присадки. At the initial sections of the Uzen - Atyrau - Samara main oil pipeline, batches of low pour point Buzachinsky and high pour point Mangyshlak oils are formed. Additional pumping of oils with different physical, chemical and rheological characteristics is carried out along the transportation route, which can have a significant effect on the properties of the pumped oil mixtures. The purpose of this study is to examine the physical, chemical and rheological properties of Buzachi and Mangyshlak oil mixtures on the Uzen - Atyrau supply route, as well as the range and causes of changes in the characteristics of Buzachinsky oil (the main oil mixture in the blend composition pumped through the Uzen - Atyrau - Samara pipeline). According to the research results, it was found that the properties of the Mangyshlak oil mixture vary within insignificant limits. The Buzachinsky oil mixture is characterized by instability of rheological parameters, which can vary in a wide range as a result of route pumping at different pipeline sections. Fluctuations of the rheological parameters of the most indicative samples of batches of the Buzachinsky oil mixture are recommended to be taken into account in order to increase the fluidity of high-viscosity oils and optimize the process modes of operation of pipelines through which such oils are pumped. Using the methods of gas chromatographic analysis of the molecular weight distribution of high-melting-point paraffins, as well as polarization microscopy, the optimal heating temperature for the introduction of a pour point depressant into the Buzachinsky and Mangyshlak oil mixtures has been determined.

RHEOLOGICAL PROPERTIES OF HUMIC SUBSTANCES OF PEAT AND BROWN COAL

2021 ◽  
pp. 169-174
Author(s):  
Ivan I. Lishtvan ◽  
Vera N. Aleinikova
Keyword(s):  
Rheological Properties ◽  
Humic Substances ◽  
Structure Formation ◽  
Humic Substance ◽  
Brown Coal ◽  
Oil Wells ◽  
Alkaline Media ◽  
Rheological Parameters ◽  
Acid Media ◽  
Brown Coals

Knowledge about structure and rheological peculiarities of drilling solutions and reagents applied for the proceeding of oil wells has significant value for the forecasting of oil wells drilling. The research results of the structure of the humic substances of peat and brown coals precipitated in different pH ranges from the standpoint of their ability to structure formation on the base of the rheological curves obtaining of the flow of their dispersions and determining of their rheological parameters in terms of their application in drilling practice are given in the article. It is established that during transition from fraction, beset into alkaline media (12.0–8.5) to fraction beset into acid media (5.0–2.0) the decrease of the rheological indicators of caustobiolate humic substance is occurred. Rheological curves of the flow of the disperse of caustobiolate humic substances of the fraction 1 and 2 are characterized for strong fossil structures, disperses of humic substances of the fraction 3 is for less strong coagulation structures. Less structured are humic substances of brown coal so that their use is preferable for the regulation of the structure and rheological peculiarities of drilling solutions.

scholarly journals Effect of Temperature and Used Ingredients on Rheological Parameters of Pancake Dough

2013 ◽  
Vol 16 (3) ◽  
pp. 63-66
Author(s):  
Peter Hlaváč ◽  
Monika Božiková
Keyword(s):  
Rheological Properties ◽  
Dynamic Viscosity ◽  
Kinematic Viscosity ◽  
Fat Content ◽  
Effect Of Temperature ◽  
Rheological Parameters ◽  
Rotational Viscometer ◽  
Two Samples ◽  
Dynamic And Kinematic Viscosity ◽  
Temperature Dynamic

Abstract This paper presents the selected rheological properties of pancake dough such as dynamic and kinematic viscosity and fluidity. The effect of used ingredients and temperature on rheological properties is investigated. Measurements were performed on three pancake dough samples. In two samples, there was used milk with a different fat content, and in the third sample, all ingredients were in a powder state. A digital rotational viscometer Anton Paar DV-3P was used for measuring the rheological properties. The principle of viscometer measurement is based on the dependence of sample resistance to probe rotation. Results of measurements are shown as graphical dependencies of rheological parameters on temperature. Exponential functions were used to express the dependencies of all rheological parameters on temperature. Dynamic and kinematic viscosity decreased, and fluidity increased with temperature. The highest values of dynamic viscosity were obtained for pancake dough from powder ingredients. A higher fat content of used milk caused higher values of dynamic viscosity.

scholarly journals Impact of systemic cryotherapy on the rheological properties of the blood in women with rheumatoid arthritis

2017 ◽  
Vol 21 (2) ◽  
pp. 4-9
Author(s):  
Bartłomiej Ptaszek ◽  
Aneta Teległów ◽  
Jakub Marchewka
Keyword(s):  
Rheumatoid Arthritis ◽  
Rheological Properties ◽  
Treatment Time ◽  
Venous Blood ◽  
Body Height ◽  
Rheological Parameters ◽  
Study Group ◽  
Mean Values ◽  
Chamber Temperature ◽  
The Mean

Study aim: The aim of this study was to assess the effects of systemic cryotherapy on the rheological properties of the blood in women with rheumatoid arthritis. Study group: The study group consisted of 10 women with rheumatoid arthritis, aged 57.2 ± 9.4, who underwent systemic cryotherapy treatments (3 min treatment time, -120 °C chamber temperature, 10 treatment sessions - 5 times a week). Their average body height was 165.5 ± 4.6 cm, weight 68.5 ± 4.9 kg and BMI 24.8 ± 2.2 kg/m2. In order to analyze morphological and rheological parameters of the blood, venous blood samples were drawn from the participants of the study twice. The first study was held on the day of beginning treatments and the second test was conducted after a series of 10 treatments. Methodology: The morphological blood test - measurements were taken using the ABX MICROS 60 (USA) hematology analyser. Erythrocyte deformability and aggregation were tested using the LORCA analyser (Laser-assisted Optical Rotational Cell Analyser RR Mechatronics, The Netherlands). The results were obtained as the index of elongation and aggregation according to the Hardeman method (2001). Results: Analysing the average values of morphological and rheological parameters of the blood in women with rheumatoid arthritis in the study group, the mean values of RBC, Hct and AI following the series of 10 treatments were significantly higher after cryotherapy in comparison to the measurements taken before treatments. Analysing the mean concentrations of T½, there was statistically significant reduction after the series of 10 treatments. Conclusions: Regular usage of cryotherapy treatments may affect the levels of morphological and rheological parameters of the blood in women with rheumatoid arthritis - RBC, Hct and AI (increase) and T½ (reduction) in the blood. null

scholarly journals Estimation of Rheological Properties of Ice Cream Unfrozen Liquid Phase by FT-NIR Spectroscopy

1970 ◽  
Vol 66 (2) ◽  
Author(s):  
Florina A. SILAGHI ◽  
Alessandro GIUNCHI ◽  
Angelo FABBRI ◽  
Luigi RAGNI
Keyword(s):  
Liquid Phase ◽  
Rheological Properties ◽  
Powder Mixture ◽  
Goodness Of Fit ◽  
Flow Behavior ◽  
Nir Spectroscopy ◽  
Ice Cream ◽  
Rheological Parameters ◽  
Good Prediction ◽  
Flow Behavior Index

The control of ice cream powder mixture production is carried out evaluating the ice cream liquid phase. The present study was conduced on ice cream and unfrozen liquid phase in order to indirectly evaluate the rheological properties by measuring the powder mixture. The calibration set was formed by samples with different percentage of thickeners, maintaining constant the concentration of the other remaining compounds. After the NIR acquisitions the powders were mixed with warm milk, blended and than settled in order to obtain the unfrozen liquid phase needed for the rheological measurements. For each recipe three batches were prepared. The flow curves were evaluated by using the Ostwald de Waele’s equation and the goodness of fit was evaluated by the R2, which was above 0.95. Predictive models of rheological parameters were set up by means of PLS regressions in order to predict the consistency coefficient (K) and the flow behavior index (n) from spectral acquisitions. High correlation of calibration was found for both parameters and NIR spectra obtaining R2 of 0.884 for K and 0.874 for n. The good prediction of the models encourages applying them to reduce significantly the time of the powder mixing control during production.

scholarly journals The influence of base oil type on the rheological properties of ecological lubricating greases

Nafta-Gaz ◽  
2021 ◽  
Vol 77 (2) ◽  
pp. 127-135
Author(s):  
Rafał Kozdrach ◽  
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Rheological Properties ◽  
Measurement Data ◽  
Measuring System ◽  
Rheological Parameters ◽  
Flow Curves ◽  
Lubricating Grease ◽  
Dispersion Phase ◽  
Base Oil

The article presents the results of research on the influence the type of base oil in lubricating compositions has on the rheological parameters of selected lubricants. Vegetable, mineral, and synthetic dispersion phases were used to produce lubricating greases. The modified amorphous silica was used as the dispersed phase. However, as a modifying additive was used a substance containing the antioxidants, corrosion inhibitors, and EP/AW additives. The experiments on rheological properties were carried out using a Physica MCR 101 rotational rheometer (manufactured by Anton Paar), equipped with a diffusion air bearing and connected to a pneumatic supply – an oil-free Jun-Air compressor and air drying block. The device is equipped with a Peltier system for temperature control in the range of –20°C to 200°C and an external thermostatic VISCOTHERM V2 system, working in the temperature range of –20°C to 200°C. The rheometer control and measurement data analysis were performed using Rheoplus software. The tests were carried out using a cone-plate measuring system with a shear rate range of 0.01–100 s-1 at 20°C for lubricating compositions prepared on various oil bases. To evaluate the value of rheological parameters, the results of tests of the dependence between shear stress and shear rate (flow curves) were used. For the theoretical determined on the flow curves, the following rheological models were used: Bingham, Herschel–Bulkley, Casson, and Tscheuschner. The values of the shear stress (yield point) in depending on the type of dispersion phase has changed. This proves that the use of a base oil with the appropriate functional properties does not weaken, but reinforces the spatial structure of a lubricating grease. It has an important meaning when selecting construction parameters when designing a central lubrication system with grease made from a vegetable oil base (Abyssinian oil). The rheological properties of the lubricating grease are influenced by the type of base oil and thickener, any additives in the grease, the production technology of the grease, and the conditions in which it is used. The tests revealed an important influence of the base oil on the rheological parameters that describe the behaviour of lubricating compositions subjected to stresses and strains in a lubricating system.

scholarly journals RESEARCH OF RHEOLOGICAL PROPERTIES OF MEDICINAL SYRUP FOR ORAL USE

2020 ◽  
Vol 73 (4) ◽  
pp. 696-699
Author(s):  
Lena L. Davtian ◽  
Galyna P. Kukhtenko ◽  
Alona S. Voronkina ◽  
Viktoria V. Kudria
Keyword(s):  
Rheological Properties ◽  
Mechanical Stability ◽  
Rheological Parameters ◽  
Dynamic Flow ◽  
Shear Rates ◽  
Coaxial Cylinders ◽  
Low Degree ◽  
Newtonian Type ◽  
Rotary Viscometer

The aim of the present research was to investigate the rheological properties of the medicinal syrup for oral administration with glucosamine hydrochloride and levocarnitine. Matherials and methods: Coefficient of the dynamic flow (at shear rates of 3,49 and 10,3 s -1, as well as at shear rates of 27.2 and 149.0 s-1), mechanical stability, the index of destruction and restoration were studied. The rheological (structural-mechanical) properties of the samples were determined using a Rheolab QC rotary viscometer (AntonPaar, Austria) with coaxial cylinders CC27 / S-SN29766. The rheological parameters were studied at the temperature 20±0,5 °С. Results: It is established that the syrup has weakly expressed plastic viscous and thixotropic properties (the hysteresis area for the syrupis 1710.19 Pas/s). Such results characterize the system as a reopex. Conclusions: The results of the study enables classification of the research object as system with a low degree of fluidity. Such dependence is typical for systems of the Newtonian type of flow and characterizes the syrup under investigation as a weakly structured disperse system.

Evidence that wax deposition is a phase transition rather than a molecular diffusion phenomenon

Fuel ◽  
2022 ◽  
Vol 313 ◽  
pp. 122940
Author(s):  
Charlie van der Geest ◽  
Letícia Bizarre ◽  
Aline Melchuna ◽  
Ivanei F. Pinheiro ◽  
Vanessa C.B. Guersoni
Keyword(s):  
Phase Transition ◽  
Molecular Diffusion ◽  
Wax Deposition ◽  
Diffusion Phenomenon

Development of New Models to Determine the Rheological Parameters of Water-based Drilling Fluid Using Artificial Intelligence

2021 ◽  
Author(s):  
Farqad Hadi ◽  
Ali Noori ◽  
Hussein Hussein ◽  
Ameer Khudhair
Keyword(s):  
Rheological Properties ◽  
High Performance ◽  
Drilling Fluid ◽  
Gel Strength ◽  
Solid Content ◽  
Rheological Parameters ◽  
Water Based ◽  
Fluid Properties ◽  
Drilling Operations ◽  
Marsh Funnel

Abstract It is well known that drilling fluid is a key parameter for optimizing drilling operations, cleaning the hole, and managing the rig hydraulics and margins of surge and swab pressures. Although the experimental works present valid and reliable results, they are expensive and time consuming. On the other hand, continuous and regular determination of the rheological mud properties can perform its essential functions during well construction. More uncertainties in planning the drilling fluid properties meant that more challenges may be exposed during drilling operations. This study presents two predictive techniques, multiple regression analysis (MRA) and artificial neural networks (ANNs), to determine the rheological properties of water-based drilling fluid based on other simple measurable properties. While mud density (MW), marsh funnel (MF), and solid% are key input parameters in this study, the output functions or models are plastic viscosity (PV), yield point (YP), apparent viscosity (AV), and gel strength. The prediction methods were demonstrated by means of a field case in eastern Iraq, using datasets from daily drilling reports of two wells in addition to the laboratory measurements. To test the performance ability of the developed models, two error-based metrics (determination coefficient R2 and root mean square error RMSE) have been used in this study. The current results of this study support the evidence that MW, MF, and solid% are consistent indexes for the prediction of rheological properties. Both mud density and solid content have a relative-significant effect on increasing PV, YP, AV, and gel strength. However, a scattering around each fit curve is observed which proved that one rheological property alone is not sufficient to estimate other properties. The results also reveal that both MRA and ANN are conservative in estimating the fluid rheological properties, but ANN is more precise than MRA. Eight empirical mathematical models with high performance capacity have been developed in this study to determine the rheological fluid properties based on simple and quick equipment as mud balance and marsh funnel. This study presents cost-effective models to determine the rheological fluid properties for future well planning in Iraqi oil fields.

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